maven-002: maven-lifecycle-phases-by-lifecycles

Here’s a complete list of all Maven lifecycle phases, categorized by each lifecycle:

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🚀 1. Clean Lifecycle (Removes Old Builds)

Phase	What It Does
pre-clean	Executes custom tasks before cleaning (if configured).
clean	Deletes the target/ directory (removes compiled code, JARs, test reports, etc.).
post-clean	Executes custom tasks after cleaning (if configured).

🛠 Command to run:

mvn clean

👉 Runs only the clean lifecycle (no compilation or packaging).

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⚙️ 2. Default (Build) Lifecycle (The Main One)

Phase	What It Does
validate	Checks that the project structure and pom.xml are correct.
initialize	Sets up the project (e.g., initializes properties, creates directories).
generate-sources	Generates source code if needed (e.g., annotation processing, codegen tools).
process-sources	Processes existing source code (e.g., applying formatting or transformations).
generate-resources	Generates additional resource files if needed.
process-resources	Copies and processes resource files (from src/main/resources to target/).
compile	Compiles Java source code (src/main/java) into .class files.
process-classes	Processes compiled classes (e.g., bytecode enhancement).
generate-test-sources	Generates test source files if needed.
process-test-sources	Processes test source files (e.g., annotations, generated classes).
generate-test-resources	Generates test resource files if needed.
process-test-resources	Copies test resources (src/test/resources).
test-compile	Compiles test source code (src/test/java).
process-test-classes	Processes compiled test classes (e.g., instrumentation).
test	Runs unit tests using a framework like JUnit or TestNG.
prepare-package	Prepares the project for packaging (e.g., signing artifacts, modifying manifests).
package	Bundles the compiled code into a JAR, WAR, or other format.
pre-integration-test	Prepares for integration testing (e.g., starting a database or server).
integration-test	Runs integration tests (tests that require an external environment).
post-integration-test	Cleans up after integration tests (stopping services, rolling back changes).
verify	Checks the packaged artifact for correctness (e.g., compliance, security checks).
install	Copies the packaged artifact (JAR/WAR) into the local repository (~/.m2/repository/).
deploy	Uploads the final artifact to a remote repository (e.g., Nexus, Artifactory).

🛠 Common commands and what they do:

mvn compile

👉 Runs: validate → initialize → process-sources → process-resources → compile

mvn package

👉 Runs: Everything up to package, creating a .jar or .war file.

mvn install

👉 Runs: Everything up to install, storing the artifact in your local Maven repository.

mvn deploy

👉 Runs: Everything up to deploy, uploading the artifact to a remote repository.

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📄 3. Site Lifecycle (Documentation & Reports)

Phase	What It Does
pre-site	Runs tasks before generating documentation.
site	Generates project documentation (e.g., javadocs, reports).
post-site	Runs tasks after documentation is generated.
site-deploy	Uploads the generated site to a remote server.

🛠 Command to generate documentation:

mvn site

👉 Creates a target/site/index.html with project reports.

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📝 Summary

Lifecycle	Phases	Runs Before Every Phase?
Clean	pre-clean → clean → post-clean	No (only runs clean tasks).
Default (Build)	validate → compile → test → package → install → deploy	Yes (runs all previous phases).
Site	pre-site → site → post-site → site-deploy	No (only runs site-related tasks).

👉 Maven only runs up to the phase you request, including all previous phases—but does not run future phases.

👉 The Default Lifecycle is the main one used in every project.

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💡 Example: Full Maven Workflow

Imagine you’re building a Java project with unit tests and want to install it locally.

You run:

mvn install

Maven automatically executes:

1. validate → Checks project structure.
2. compile → Compiles Java files.
3. test → Runs unit tests.
4. package → Creates a .jar or .war.
5. install → Stores the .jar/.war in your local repository (~/.m2/repository).

If you then want to publish the artifact to a remote repository, run:

mvn deploy

This executes:

1. deploy → Uploads the artifact to a central repository.

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🎯 Key Takeaways

• The Default Lifecycle is the most important (it handles compilation, testing, and packaging).
• Every phase runs all previous phases in its lifecycle.
• Maven only runs what’s needed—it won’t run extra phases unless required.
• The Clean Lifecycle runs separately (it won’t trigger compilation).
• The Site Lifecycle is for documentation and reports.

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